Macsense Connectivity Digital Wattmeter DWM-4 Product Manual

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Welcome: Thank you for your purchase of the DWM-4 Digital Wattmeter. The DWM-4 represents
an advancement in technology that has never before been available in RF power measurement.
With the integration of a microprocessor to existing RF sensor technology, the DWM-4 offers the
flexibility of digital processing while keeping the interface to the user simple and straightforward.

Introduction: The DWM-4 is a four channel, microprocessor controlled RF wattmeter. It consists
of two main parts, the display unit and the remote sensor. The display unit has a 2 by 16 backlit
LCD module that provides the user with information about the RF that is being sampled by the
remote sensor. The user can simultaneously view forward power, reverse power and swr on the
same display for instant analysis of the antenna system.

There are two types of remote sensors. The HF/QRP sensor can sample RF from 1.8 to 54 MHz
and up to 150 watts. The VHF/UHF sensor can sample RF from 140 to 160 and 420 to 470 and up
to 150 watts. The modular design allows for the maximum flexibility with the minimum cost. The
remote sensor is supplied with a six-foot cable to connect to the display unit. A longer cable can be
used for truly remote sensing.

The display unit is controlled by a selection of menu screens on the display. The menu screens
and the data on them are selected by the two pushbuttons (Menu and Select) on the front panel.
Status information is also shown on the display.

Building the Kit: If you purchased the DWM-4 as a kit, the following instructions will give an
overview of how to assemble it. If the DWM-4 was purchased assembled, you may still want to
review the assembly instructions to become more familiar with the unit. If you want to get right to
operating the unit, skip the assembly instructions and go right to the operation section.

Before getting the soldering iron out, go through all of the parts in the kit and familiarize yourself
with each component and its placement. Most of the parts are common, but there may be a few of
them that may be new to some builders. There are just over 100 parts and 200 solder connections,
so take your time.

The instructions are written to assemble the unit using the height order of the parts form lowest to
highest. This will assist the builder in the installation of the components. There are various photos

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in the assembly instructions to assist the builder. These can be used for parts identification and PC
board placement.

Assembly: You will first install (locate, place, and solder in place) the parts on the DWM-4 Main
PC board. Use the silk screen layout in the back of this manual to assist in locating where parts
are to be installed.

___ Install all of the resistors, R2, 8, 22, 26, 29 and 30. Be sure to check the values with the parts list.

Most of the resistors are 1/8 watt and may be hard to read. Use an ohmmeter to verify the values if

you have trouble identifying them.
___ Install the 1N4001 diode, D1. Note the band polarity.
___ Install the 1N4148 diodes, D2-5. Note the band polarity.
___ Install the 10K 10-pin SIP resistor, RP1. Be sure to note the orientation of the SIP resistor. A small

line (or dot) on the side with writing marks pin 1.
___ Install the .01uf monolithic capacitors, C1, 3-5, 7-10, 12-15, 17-20, 22-25.
___ Install the ceramic capacitors, C6 100pf 1KV; C26 & 27 10pf 500v.
___ Install U2, the 7805. Align the .2" hole in the regulator with the .2" hole in the PC board. Solder

and clip the three legs. Then place one screw through the bottom of the PC board, through the

hole in the 7805 and tighten a nut on it from the top of the PC board.

___ Install the 2N3904 transistor, Q1. Note the correct orientation.
___ Install the variable resistors (100K pots), R5-6, 11-12, 17-18, 23-25.
___ Install the socket for U3, 14-pin DIP socket. Match the notch on the silk screen with the notch on

the socket. Do not install the U3 (the LM339) until later.

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___ Install the socket for U1. Note the orientation of the socket. The flattened corner goes in the upper

left, toward the 14-pin DIP socket for U3. Do not install U1 (the 68HC11) until later.
___ Install the 8 MHz crystal.

___ Install the electrolytic capacitor, C2, 10uf radial. Note the polarity.
___ Install the 1/8" stereo jacks, J1-5.
___ Install the power jack, J6.
___ Install the 10-pin header, J7. Solder the shorter ends of the pins to the PC board.
___ Install the 14-pin header, J8. Solder the shorter ends of the pins to the PC board.
___ Install the relay K1. Be careful not to bend the pins over pushing them in.

You are finished with the assembly of the DWM-4 Main PC board. Proceed with the assembly of the
Front Panel PC board.

Assembly of the DWM FP PC board.

___ Install the 10 pin header (J7) with 0.1 inch spacing to the side of the front panel PC board that has

the white silk screen. (In copper you can read "Place connector this side". Solder the shorter

ends of the pins to the PC board.
___ Unwrap the chassis (bottom part of the enclosure) and put the 4 rubber feet on the bottom.

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___ Install the LCD Module in the chassis. Use the 4 black flat head screws, the two #4 nylon washers

and four nuts. Use the washers on the Status/SWR side of the chassis. Do not over tighten the

mounting screws.

___ Install the SPST toggle switch (SW1) in the chassis in the Power On position. Remove the nut

and one washer from the switch. Place the switch in the hole with the 2 prongs toward the bottom.

Then replace the lock washer and nut on the switch. You may need to re-align the switch later, so

don't tighten yet.
___ Install the 2 push button switches (PB1 & PB2) in the chassis in Menu and Select positions.

Remove the nut and washer from the switch. Place the switch in the hole and replace the washer

and nut on the switch. Be sure the solder terminals of the switches are aligned one on top of the

other. You may need to realign the switches later, so don't tighten yet.
___ Place the LEDs in the front panel board, D1 Green, D2 Yellow. Be sure to place ground side

down. The ground leg of the LED is the one with the notched plastic next to it. Do not solder them

at this time.
___ Install the Front Panel PC board on the switches. The side without the white silkscreen will be

placed on the solder terminals of the switches. Gently push the pc board onto the switches. The

LEDs should slide into the holes in the chassis. Once you have checked the alignment, then solder

the switches to the pc board. Tighten the nuts on the switches at this time. Next, slide the LEDs

into the chassis and solder the legs to the pc board. Then clip the legs of the LEDs.